1. Field of the Invention
Exemplary embodiments relate to an electronic device, and more particularly, relate to a data storage device and an operating method thereof.
2. Description of the Related Art
In computer systems, host may be interconnected with peripheral devices, such as data storage device, printer, scanner, etc., via the standardized interface. The standardized interface means the protocol with respect to a command set and mechanical and electrical requirements necessary to interconnect host and peripheral devices.
The standardized interface for interconnecting host and peripheral devices may include various interfaces: Advanced Technology Attachment (ATA) interface, Serial ATA (SATA) interface, external SATA (e-SATA) interface, Small Computer Small Interface (SCSI), Serial Attached SCSI (SAS), Peripheral Component Interconnection (PCI) interface, PCI-Express (PCI-E) interface, IEEE 1394 interface, Universal Serial Bus (USB) interface, Secure Digital (SD) card interface, Multi Media Card (MMC) interface, embedded MMC (eMMC) interface, Compact Flash (CF) card interface, and the like.
Among the above interfaces, SCSI and SAS interfaces are widely used at server or workstation. SAS interface may interconnect host and peripheral devices via SCSI command sets. SCSI interface may utilize parallel transfer manner which uses a plurality of signal lines. In case of parallel transfer manner, a problem may arise due to a plurality of signal lines when a clock frequency becomes higher to transfer signals in a high speed. For example, the program may include the skew that data signals simultaneously transferred from a transmitter side via a plurality of signal lines are dispersed and then dispersed data signals arrive at a receiver side. Alternatively, the program may include crosstalk that interference arises due to mutual induction among data signals transferred via a plurality of signal lines.
As improved SCSI interface, SAS interface may use serial transfer manner to overcome problems caused by parallel transfer manner. Accordingly, SAS interface may interconnect host and peripheral devices via SCSI command sets and may use serial transfer manner where single signal fine is adopted. SAS interface may use a high clock frequency to conduct high-speed transmission.
With SCSI interface, one SCSI bus connected with host can be shared by a plurality of peripheral devices. On the other hand, with SAS interface, respective peripheral devices can be connected to one SAS bus in a point-to-point manner. With SCSI and SAS interfaces, host may transfer new command to peripheral device before there is received information indicating that command previously transferred from peripheral device is completed. Accordingly, host and peripheral device connected via SCSI or SAS interface may grant unique identifiers to commands in order to manage and perform command.